Cytomegalic inclusion disease (CID), generalized salivary gland virus disease, cytomegaly, and inclusion disease are synonyms for an illness caused by cytomegalovirus (CMV) infection. CMV is involved in a wide spectrum of clinical disorders from inapparent infection to serve congenital disease. Weller, T., N. Engl. J. Med., 285, 203 and 267 (1971).
For example, disease occurs in patients on immunosuppressive therapy and in those subject to opportunistic infections. In fact, CMV has become the most common infection after allogeneic bone marrow transplantation and is an important determinant of the success or failure of the transplant procedure [Neiman et al., J. Infect. Dis., 136, 754 (1977)].
Among adults undergoing immunosuppressive therapy after renal homotransplantation, over 90 per cent develop an active cytomegalovirus infection if they have cytomegalovirus antibody prior to surgery. Approximately half of the seronegative patients subsequently become infected on immunosuppressive therapy. Seronegative recipients receiving a kidney from a seropositive donor almost always develop a postoperative infection and are likely to develope symptoms.
Cytomegalovirus (CMV) infection is caused by a species-specific agent with the physio-chemical and electron microscopic characteristics of a herpesvirus. Human CMV was first isolated in fibroblastic tissue culture in the mid-1950's from infants with CID and from the adenoid tissue of schoolage children. A cytopathic effect was noted in tissue culture which was characterized by large intranuclear inclusions. The propagation of the virus provided the basis for the development of specific serologic tests as will be described.
Cytomegalovirus infection is worldwide in distribution. Cytomegalovirus, however, does not induce a highly communicable infection. Thus, a substantial number of individuals remain susceptible to the infection in adult life. CMV has been isolated from saliva, the upper respiratory tract, urine, milk, cervical secretions, semen, feces and circulating leukocytes in blood. The virus is probably transferred by intimate contact with an infected individual or by infusion of blood from a asymptomatic blood donor.
Specifically, a type of cytomegalovirus infection has been described in patients who have received blood transfusions. This condition, referred to as post-transfusion CMV mononucleosis, occurs two to four weeks after the administration of blood.
Acquired cytomegalovirus infection has also been associated with autoimmune hemolytic disease, ulcerative lesions of the gastrointestinal tract, post-transplantation pneumonia and thrombocytopenic purpura. For the majority of CMV infections acquired after birth, however, recover is without significant complications.
The diagnosis of cytomegalovirus infection in a patient with mononucleosis-like symptoms can be established by virus isolation from vesicular lesions. Antibodies produced in response to infection with a CMV can be detected by neutralization (NT), complement-fixation (CF), immunofluorescence and platelet-agglutination (PA) procedures. [See Weller, T. H., N. Engl. J. Med., 285, 203 (1971)]. Currently available serologic tests, however, must be interpreted with caution when diagnosing CMV infection because of cross-reactions with other cell-associated herpesviruses, and, for example, the tendency of CF antibody to fluctuate widely in normal subjects.
There is no satisfactory treatment for cytomegalovirus infections. The use of corticosteroids, gamma globulin and antiviral drugs such as deoxyuridine, floxuridine, cytosine arabinoside and adenine arabinoside have been reported with equivocal, beneficial, or no effect on the clinical course. But these reports are difficult to evaluate because of the small numbers of individuals treated, the multiple factors operating simultaneously and the variablity of virus excretion in individuals tested at different times.